Many industries are involved with the use of thread-like elements including thread, twine, yarn, cables, or other thread-like elements which are combined to form a finished workpiece. Often one or more of the thread-like elements break during the combining operation and a quality workpiece is not produced. In the sock knitting industry, for example, sets of a plurality of threads each are fed to a knitting machine to produce the sock. One set, comprising several threads, is employed to make up the upper section of the sock, this being effected at one time, and another set of threads is employed to make up the foot section of the sock, this operation properly occurring at a preceding or following time. If one thread of the plurality of threads that goes to the foot portion, for example, is broken, and if the machine is allowed to continue to run, a sock which is imperfect will result. This is true also for the top portion. Further, if both operations are attempted at the same time, this should be noted and indicated.
Applicants are aware of at least one system wherein, by means of microswitches related to each thread or thread-like element to be run, there can be signalled the specific threads that are to be run; and then by the detection of threads actually running, an error condition may be detected. However, where the same number of threads are running but different threads (threads of another color) are running, which is the common practice in the fabrication of clothing such as socks, as at different stages of production of a sock, such a system would indicate an error where none existed.
Accordingly, it is an object of this invention to provide an error detection system or monitor which overcomes the "different thread" problem and indicates an error state only when the number of threads running is an error.
It is a further object of the present invention, therefore, to provide a monitoring system which will continuously monitor and will enable warnings and/or rapid, automatic shutoff of an apparatus used in combining thread or thread-like elements which go into producing a finished product when a faulty operation is detected.
It is another object of the present invention to provide such a monitoring system which will indicate the operational state of movement of discrete thread-like elements.
It is yet a still further object of the present invention to provide such a system for the prevention of the production of imperfect socks.